Fisher® 4800 pages
480 Series Actuators
nnnnD100091X012
nnnnProduct Bulletin
nnnn61.2:480
nnnnFebruary 2013
nnnnFisher® 480 Series Yokeless Piston Actuators
nnnnFisher 480 Series actuators are yokeless piston
nnnnactuators that are used in either throttling or on-off
nnnnapplications with ball valves, butterfly valves, louvers,
nnnndampers, and rheostats. They require pneumatic
nnnnpressure loading from double-acting positioners
nnnn(Fisher 3570) or from on-off loading and unloading
nnnndevices.
nnnnFeatures
nnnn■ Actuator Versatility—Actuator with or without
nnnnpositioners and snubbers is available in an
nnnnassortment of sizes, stroking speeds, thrusts, and
nnnntravels to handle most control requirements.
nnnn■ Compact Design—Yokeless construction permits a
nnnnlow-profile assembly by allowing close coupling to
nnnnthe control device; either through a bracket or, with
nnnnsome versions, by direct mounting on a bonnet
nnnnflange.
nnnn■ Wide Range Supply Pressure Capability—The
nnnncylinder (and 3570 positioner if used) can operate
nnnnwith supply pressures as low as 2.4 bar (35 psig) or
nnnnas high as 10.3 bar (150 psig).
nnnn■ Long Stroke—Actuators have maximum rated
nnnntravels of up to 206 mm (8.125 inches).
nnnn■ Positioner Versatility— Positioner/actuator action is
nnnneasily reversed in the field with no additional parts.
nnnnPositioner sensitivity, travel span, and travel starting
nnnnpoint are factory set and need to be reset only if
nnnnoperating conditions have changed or if the
nnnnpositioner has been reversed. See figure 1.
nnnnFisher 480-15 Piston Actuator
nnnnActuator Frequency
nnnnResponse
nnnnFigure 3 shows how various size actuators respond
nnnnwhen the input supply pressure is cycled at small
nnnnamplitude (3 to 5 percent) and increasing frequency.
nnnnAssume the cycling supply pressure and the
nnnnmovement of the actuator rod are represented by sine
nnnnwaves. As the actuator rod is forced to move faster, its
nnnnmotion begins to fall behind the input in both time
nnnn(shown as phase lag) and amplitude (shown as
nnnnnormalized gain). Both of these parameters are
nnnnaffected by the inertia of the actuator and,
nnnnconsequently, changes are more pronounced in the
nnnnlarger constructions.
nnnnEMERSON
nnnnwww.Fisher.com
nnnnProcess Management
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